Effects of exercise and oral antioxidant supplementation enriched in (n−3) fatty acids on blood oxidant markers and erythrocyte membrane fluidity in horses

Effects of supplementation with combination of polyunsaturated oils in diet of horses in maintenance and during marcha training

Abstract This study aimed to evaluate the effects of supplementation with polyunsaturated oil on lipid and mineral blood biomarkers in two different groups of horses. Was used 6 healthy horses in maintenance (MT-g) and 10 healthy horses in marcha gait training (GT-g). The MT-g and the GT-g received 100mL and 300mL/day/animal of combination of polyunsaturated oils, respectively, during 8 weeks. Blood was collected in pre-test and after 4 and 8 weeks, after overnight fasting and it was measured: total cholesterol, HDL cholesterol, LDL cholesterol, triglyceride, NEFA, LPS, glycerol, Ca, P, Mg, and Cl. The supplementation produced significant increase in NEFA and reduction in lipase in both groups. In addition, the LPS content in both groups had a large decrease (~35%) from the pre-test to the 8th week of supplementation. In the MT-g, the LDL cholesterol and glycerol increased significantly after 4 weeks but returned to the pre-test levels after 8 weeks, and the triglyceride content decreased (~62%) after 4 weeks. The total cholesterol concentration in the GT-g increased after 4 weeks (~70%), but after 8 weeks it decreased to levels similar to those observed in the pre-test. The mineral biomarkers increased in the MT-g and GT-g, after 8 weeks. In the MT-g and in the GT-g, Ca decreased. In conclusion, supplementation with a combination of polyunsaturated oils increased NEFA concentration and reduced LPS activity in both groups, unlike the concentrations of the other biomarkers that showed different variations between groups, indicating that both NEFA and LPS the changes in their concentrations during supplementation may be more sensitive and more indicated for these types of evaluation. In addition, some blood mineral concentrations reduced significantly in both groups of horses, and thus, they need to be evaluated in horses under chronic oil supplementation

Use of oil-rich diet for gaited horses during physical training

In Brazil, gaited horses are selected based on field tests, during which they move at speeds of 3 to 4 m/s for 30 to 60 min. To cover their nutrient requirements, feed manufacturers have developed oil-rich dietary supplements and concentrates. The aim of this research was to evaluate the effects of increasing the density of dietary fats in the feed of 16 Campolina horses undergoing intense gaited training. The training schedule consisted of training 4 × a week: 3 days riding for 60 min (10' warm-up, 40' doing marcha gait, and 10' cool down, and 1 day walking for 90'). The horses were divided in two groups: control and supplemented. The dietary supplementation was isocaloric, with the control group receiving an ordinary concentrate (3.5% fat) and the supplemented group fed 1.0 kg of the supplement (18% fat) plus the ordinary concentrate. Both groups had free access to fresh grass, salt and water. Blood samples were collected prior to and after 4 and 8 weeks of supplementation to calculate the complete blood count, glucose, total protein, triglycerides, total cholesterol, HDL, LDL and non-esterified fatty acids (NEFA). The results were evaluated by ANOVA and Tukey's test (P < 0.05). The supplemented group showed elevated levels of NEFA, red blood cells and haematocrit (P < 0.05), while the control group showed high triglyceride concentrations; both groups showed reduced plasma protein concentrations (P < 0.05). The other indices did not change (P > 0.05). The increase in dietary fat intake increased the blood lipid biomarkers and antioxidant capacity of gaited horses during intense training, possibly contributing to improve their metabolic performance.

Survey of biochemical and oxidative profile in donkey foals suckled with one natural and one semi-artificial technique

Dairy donkey milking procedures require separating foals from their dams for a few hours a day. Artificial suckling in this species is a good technique for improving milk production and foal welfare. The aim of the work is to compare the effect of two different diets on donkey foals when separated from jennies for milking procedures with and without a milk replacer. Forty newborn Martina Franca donkey foals were subdivided into two experimental groups. Both groups were separated from their respective dams from 8.00to 20.00to allow the jennies to be milked. During the separation, all the foals had access ad libitum to water, hay and feed. During the separation period, one group had the availability of a mechanical milk replacer dispenser, so foals were partially artificially suckled (AS), while the other group had no milk replacer available, and so were totally naturally suckled (NS). The AS group had milk replacer availability until 120±7d of life. Both groups were naturally weaned at 168±7d. Blood samples were collected weekly starting from birth until two wks after weaning (i.e. at 182d), from all the foals included in the trial. Almost all the analytes were influenced by suckling technique and age of foals. Alanine-aminotransferase, aspartate-aminotransferase, alkaline phosphatase, NEFA, lipid hydroperoxides, serum proteins showed the greatest differences between the two experimental groups. Separating foals from their dams for 12hdaily for 24 weeks does not lead to pathological subclinical and metabolic conditions, thus confirming the high rusticity and resistance of the donkey.

Subclinical diseases underlying poor performance in endurance horses: diagnostic methods and predictive tests

Thirty-eight endurance horses underwent clinical and ancillary examinations, including haematological and biochemical evaluation, standardised exercise tests both on a treadmill and in the field, Doppler echocardiography, impulse oscillometry, video endoscopy and collection of respiratory fluids. All of the examined poorly performing horses were affected by subclinical diseases, and most of them had multiple concomitant disorders. On the contrary, the well-performing horses were free of any subclinical disease. The most frequently diagnosed diseases were respiratory disorders, followed by musculoskeletal and cardiac problems. Poor performers exhibited lower speeds at blood lactate concentration of 4 mmol/l (VLA4) and at heart rates of 160 (V160) and 200 bpm (V200) on the treadmill and in the field, as well as slower recovery of heart rate.

Modulation of circulating purines and pyrimidines by physical exercise in the horse

This study was designed to examine the influence of sub-maximal exercise on purine and pyrimidine catabolism in horses. Ten horses were initially trained for 12 weeks at the end of which they underwent a standardized exercise test (SET); venous blood samples were taken at rest, 5 and 30 min after the SET. Six untrained healthy horses, from which a blood withdrawal was taken at rest, were used as the control group. Samples were analyzed by HPLC for the simultaneous determination of uric acid, uridine, β-pseudouridine and creatinine in plasma. Glucose and lactate were measured in blood. Trained horses had basal uridine levels significantly lower than sedentary horses. The SET caused significant increase in plasma uric acid, uridine, β-pseudouridine and creatinine. Following the SET, a significant negative correlation was found between plasma uridine and glucose, whilst a significant positive correlation was observed between plasma uric acid and creatinine. These results indicate that increase in energy demand during exercise in the horse causes not only the degradation of purine but also of pyrimidine compounds, the latter possibly exerting a control on glucose uptake as also demonstrated in human beings.

Whole blood selenium concentrations in endurance horses

Exercise causes an increase in the production of reactive oxygen species, which can result in oxidant/antioxidant disequilibrium. Deficiency of antioxidants can further alter this balance in favor of pro-oxidation. Selenium (Se) is one of many antioxidant catalysts, as a component of the glutathione peroxidase enzymes. Soils and forages vary widely in Se concentration and a deficient diet can lead to sub-clinical or clinical deficiency in horses. Endurance horses are prone to oxidative stress during long periods of aerobic exercise and their performance could be affected by Se status. This study investigated the blood Se concentration in a group of endurance horses (n=56) residing and competing in California, a state containing several regions that tend to produce Se-deficient forages. The rate of Se deficiency in this group of horses was low, with only one horse being slightly below the reference range. Higher blood Se concentrations were not associated with improved performance in terms of ride time. There was no significant difference in Se concentration between horses that completed the ride and those that were disqualified, although blood Se concentrations were significantly higher in horses that received oral Se supplementation. An increase in blood Se concentration was observed following exercise and this warrants further study.

Protecting effect of vitamin E supplementation on submaximal exercise-induced oxidative stress in sedentary dogs as assessed by erythrocyte membrane fluidity and paraoxonase-1 activity

The aim of this placebo-controlled study was to investigate the effects of oral vitamin E supplementation for 10 weeks on exercise-induced oxidative damage in untrained dogs. Eight dogs were randomly assigned to a supplementation (n=4) or control (n=4) group and underwent two isolated submaximal exercise sessions, 10 weeks apart. Blood was collected during each session to measure erythrocyte membrane fluidity (EMF), paraoxonase-1 (PON1) activity, plasma malondialdehyde (MDA) and vitamin E concentrations. These biomarkers were measured in venous blood samples collected before (t(0)), just after (t, EMF only) and 1d (t+1d) and 7d (t+7d) after the dogs ran on a treadmill. Prior to vitamin E supplementation, exercise induced a significant decrease in PON1 activity, EMF, vitamin E concentration and a significant increase in MDA concentration at t+1d. After a 10 week vitamin E supplementation period, these exercise-induced changes in PON1 activity, EMF and MDA concentration were still significant in the control group, but not in the supplemented group. These results suggested that vitamin E supplementation had a protective effect on submaximal exercise-induced oxidative damage in sedentary dogs.

The oxidant/antioxidant equilibrium in horses

Since "free radical research" started in 1954, understanding the role of oxidants and antioxidants in physiological and pathological conditions has increased continuously. Oxidants are essentially generated by metabolic enzymes, inflammatory cells and mitochondrial electron leakage; they are indispensable for the cellular redox regulation and may, under certain conditions, have a pro-inflammatory stimulatory role. Endogenous and exogenous antioxidants counterbalance the oxidative processes and so maintain the oxidant/antioxidant equilibrium. Excessive oxidant generation or antioxidant insufficiency can lead to oxidative stress. The aims of this review are: (1) to provide an insight into the concept of the oxidant/antioxidant equilibrium by briefly introducing the oxidant and the antioxidant systems; (2) to describe how the oxidant/antioxidant equilibrium or oxidative stress can be evaluated in horses, and (3) to summarise current knowledge about oxidative stress in equine medicine and equine exercise physiology.